2 * Copyright (c) 1997 Kungliga Tekniska Högskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the Institute nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * Hash table functions
40 RCSID("$Id: hash.c,v 1.8 1999/12/02 17:05:02 joda Exp $");
42 static Hashentry *_search(Hashtab * htab, /* The hash table */
43 void *ptr); /* And key */
47 int (*cmp) (void *, void *),
48 unsigned (*hash) (void *))
55 htab = (Hashtab *) malloc(sizeof(Hashtab) + (sz - 1) * sizeof(Hashentry *));
56 for (i = 0; i < sz; ++i)
69 /* Intern search function */
72 _search(Hashtab * htab, void *ptr)
78 for (hptr = htab->tab[(*htab->hash) (ptr) % htab->sz];
81 if ((*htab->cmp) (ptr, hptr->ptr) == 0)
86 /* Search for element in hash table */
89 hashtabsearch(Hashtab * htab, void *ptr)
93 tmp = _search(htab, ptr);
94 return tmp ? tmp->ptr : tmp;
97 /* add element to hash table */
98 /* if already there, set new value */
99 /* !NULL if succesful */
102 hashtabadd(Hashtab * htab, void *ptr)
104 Hashentry *h = _search(htab, ptr);
110 free((void *) h->ptr);
112 h = (Hashentry *) malloc(sizeof(Hashentry));
116 tabptr = &htab->tab[(*htab->hash) (ptr) % htab->sz];
121 h->next->prev = &h->next;
127 /* delete element with key key. Iff freep, free Hashentry->ptr */
130 _hashtabdel(Hashtab * htab, void *ptr, int freep)
136 h = _search(htab, ptr);
140 if ((*(h->prev) = h->next))
141 h->next->prev = h->prev;
148 /* Do something for each element */
151 hashtabforeach(Hashtab * htab, int (*func) (void *ptr, void *arg),
158 for (h = htab->tab; h < &htab->tab[htab->sz]; ++h)
159 for (g = *h; g; g = g->next)
160 if ((*func) (g->ptr, arg))
164 /* standard hash-functions for strings */
167 hashadd(const char *s)
168 { /* Standard hash function */
179 hashcaseadd(const char *s)
180 { /* Standard hash function */
190 #define TWELVE (sizeof(unsigned))
191 #define SEVENTYFIVE (6*sizeof(unsigned))
192 #define HIGH_BITS (~((unsigned)(~0) >> TWELVE))
195 hashjpw(const char *ss)
196 { /* another hash function */
199 const unsigned char *s = (const unsigned char *)ss;
202 h = (h << TWELVE) + *s;
203 if ((g = h & HIGH_BITS))
204 h = (h ^ (g >> SEVENTYFIVE)) & ~HIGH_BITS;